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  • Question 1

Option A (“Abe only”). Most of you (89%) got this.

Abe is correct–this is essentially what Nagel says (“But that doesn’t seem enough to make something a pain”). Gene is incorrect–Nagel didn’t go that way. If anything, the fact that he seems to prefer a dual aspect theory suggests the opposite. Dave is incorrect–Nagel’s argument on p. 36 isn’t that physicalists looked only to human brain states, as if their mistake can be corrected if they expanded their account to include the brain states of other animals. Nagel brings up the other animals to drive home the point that we “won’t have an adequate general conception of the world” until we can explain how physical states can give rise to consciousness (i.e., in both animals and humans).


  • Question 2 MRQ

Options A (Gene), B (Lena), C (Tess). A majority of you (54%) got this.

Let’s look at what each person said.

Gene: “A Dual Aspect Theorist who comes to accept Mind-Body Reductionism would have to become a Reductive Physicalist.”

This is correct. Like the Reductive Physicalist, the Dual Aspect Theorist accepts “We are Physical Things” but reject Mind-Body Reductionism (see Slides #21-22); but not all Dual Aspect Theorists accept Mind-Body Dependance. However, since Mind-Body Reductionism implies Mind-Body Dependence (Slide #20), if our (ex-)Dual Aspect Theorist accepted the former, she will also need to accept the latter, and this turns her into a Reductive Physicalist. Most (92%) got this.

Lena: “A Dual Aspect Theorist might claim that two people who are completely physically identical are nevertheless experiencing completely different mental experiences.”

Tess: “A Dual Aspect Theorist might claim that two people who are completely physically identical must be experiencing exactly the same mental experience.”

Lena and Tess were both right because Dual Aspect Theorists are divided on Mind-Body Dependence. Recall that Mind-Body Dependence involves the idea that mental characteristics supervene on physical characteristics (Slide #17). So if all we know is that someone is a Dual Aspect Theorist, then it might be that he would say that mental properties supervene on physical properties (what Tess is saying), or the opposite (what Lena is saying). Almost all of you (95%) got what Lena is saying, but fewer (67%) got what Tess is saying.

Dave: “Dual Aspect Theorists face the challenge of explaining how a purely physical substance could causally interact with a purely mental substance.”

Dave was wrong because Dual Aspect Theorists do not claim that the mind and body are distinct substances–they agree with the Reductive Physicalist that we are basically physical things. What they are saying, having rejected Mind-body dualism, is we are a physical thing with both physical and mental attributes. As such, they do not make any claims about any causal interactions between physical and mental substances. Almost all of you (94%) seem to have understood this, good!


  • Question 3

Option B (“Dave only”). Almost all (98%) got this–good job!

Tess is wrong because having a unique set of fingerprints is not an example of a subjective fact. Other people are still able to access the fact that this person has this unique set of fingerprints (how fingerprint records allow investigators–other people–to identify suspects in a criminal case). What matters in the relevant objective/subjective distinction is the ability to access that fact, not that the fact uniquely applies to that person.

Dave is correct because heat understood as molecular motion is an objective fact, but which can also go along with subject facts, e.g., the subjective experience of the heat sensation. (This is analogous to the lightning example from Slide #31 by Neil Campbell.) Both the aliens and we can access heat as molecular motion, without experiencing how heat feels in the same way.

Lena is wrong because Nagel makes the more modest point that Reductive Physicalism is either false or if true, we don’t know how it is so (see Slide #36).


  • Question 4

Option C (“Abe only”). Most of you (85%) got this!

A recap–Domain A supervenes on Domain B = There can be a difference in A only if there is a difference in B (Slide #17). You can also flip it around to say If–there is a different in A, then there is a difference in B. Given Dave’s claim (“…obviously how delicious a particular serving of Nasi Lemak is supervenes on the quality and quantity of ingredients used”), domain A = how delicious a serving of Nasi Lemak is, and domain B = quality and quantity of ingredients used in the making.

Lena: “Great! Chomp Pan Nasi Lemak uses better quality ingredients, and more of it, so if Dave is right, then they definitely serve a more delicious Nasi Lemak than Pong Goals.”

Lena does not have the correct understanding of supervenience. Her statements imply that, for her, if there is a difference in the quality and quantity of ingredients (Domain B), then there is a difference in how delicious the nasi lemak is (Domain A).

Gene: “Look, Xiayu said that they’re as delicious as each other. I just suggested that we go to  Pong Goals because it’s closer to my house. But if both Dave and Xiayu are right, then, the two joints serve Nasi Lemak with ingredients of the same quality and quantity.”

Gene also does not have the correct understanding. His statements imply that, for him, if there is no change in Domain A, then there is no change in Domain B. This is the contrapositive of what Lena said, and the wrong understanding of supervenience for the same reasons.

Abe: “Hold on, there could be two Nasi Lemak joints which use the same quality and quantity of ingredients in their servings, but cook their Nasi Lemak differently so that one is more delicious than the other. If that is true, then what Dave said is wrong.”

Abe is right. If it is possible for there to be a difference in Domain A without there being a difference in Domain B, it would follow that Domain A doesn’t supervene on Domain B. If so, he would have properly disagreed with Dave.


  • Question 5

Option D (“Neither Dave, Will, nor Gene”). Most of you (80%) got this, though some (16%) were distracted by Option A (“Dave only”).

Dave is incorrect. The scenario is analogous to Nagel’s hypothetical situation where one’s brain tastes like chocolate when one is eating chocolate. As far as Nagel is concerned, the scientist licking the brain of the chocolate-eater can at best give the scientist the taste of chocolate from his first-person perspective; but this isn’t the same as giving him access to the chocolate-eater’s first-person perspective on the taste of chocolate. So likewise in this scenario. Dr. Head now sees the world “from Joshua’s first person’s perspective” only in the sense that he has the visual experience of what can be seen from Joshua’s (physical) position. But Nagel would insist that Dr. Head is experiencing this from his own first-person perspective, with his own qualia, rather than from Joshua’s first-person perspective.

All three major theories are compatible with the scenario, so neither Will nor Gene are correct. (The scenario is not very different from having the subject wear some sort of Google Glass and having the video footage captured–which is presented in exactly the same visual aspect and calibrated to the right colors, etc.–on a screen.)


  • Question 6

Options B (Gene) and C (Joan) only. Only 28% got this.

To recap what Philip said:

[Philip’s doctor] said that the fact that I [=Philip] am physically sick is entirely due to my anxiety. My stomach aches, losing sleep, even losing my hair! All of this because I am so stressed-out.

In other words, according to the doctor, Philip’s ailments (stomach aches, losing sleep, losing hair) are entirely due to his anxiety. Let’s see what each person said.

Dave: “If it is really the case that your anxiety has an impact on your body, then Mind-Body Dualism cannot be true. This is why it is regarded as an ‘outdated theory’; it belongs to a time when science couldn’t explain the causal interaction between mental and physical things.”

Dave is incorrect. Speaking more abstractly, the Dualist owes us an account of how two completely distinct substances (mind and body) can still interact, assuming he agrees that they do; but this, by itself, does not show that Mind-Body Dualism is false. So fact that Philip’s has an impact on his body wouldn’t make it such that “Mind-Body Dualism cannot be true”–even if we interpret the “anxiety” as a purely mental phenomenon and so something that can only occur in a purely mental substance given Dualism. But in fact, we don’t even know if this “anxiety” is a purely mental phenomenon (see also Gene’s statement). (32% of you picked this.)

Gene: “But if Reductive Physicalism is true, then the Doctor is technically incorrect in her diagnosis if by “anxiety”, she meant the purely mental state of feeling stressed, etc. For, given these suppositions, it can’t be that you are physically sick entirely due to your anxiety–I’m assuming that she meant by that that your anxiety explains your other physical ailments.”

Gene is correct. The doctor says that Will is physically sick “entirely due to” the anxiety. As Reductive Physicalism includes the idea of Mind-Body Dependence, it follows that physical characteristics explain mental characteristics, not the reverse (see Slide #). So if the “anxiety” is understood as the purely mental state of feeling stressed, then it can’t be the explanation for Philip’s (other) physical ailments (the hair loss, let’s say). However, if what the doctor meant by “anxiety” include the physical processes underlying the mental state of feeling stressed, then those physical processes can explain Philip’s (other) physical ailments given mind-body reductionism. (84% of you picked this.)

Joan: “If stress is a purely mental state, someone who experiences this form of mental pain might not experience the other physical ailments that Philip suffers from. And this is true whichever of the three main theories is true!”

Joan is correct. Even given Mind-Body Reductionism, what follows is that you can’t have the mental stress without there being also the appropriate physical conditions; but this doesn’t mean that the mental stress must always go together with those specific (other) ailments that Philip suffers from. Put another way, a Reductive Physicalist will insist that the anxiety–as mental phenomenon–is fully reducible to some set of physical processes. Chemicals, electrical discharges, etc. But whether that entire package involved in the anxiety is always correlated with, e.g., stomach aches, sleep loss and hair loss, isn’t something that any of the three theories can determine (that’s something for medical science to figure out). (47% of you picked this.)

A student wrote in to ask–but wouldn’t the Reductive Physicalist not even believe that there’s such a thing as “stress-understood-as a-purely-mental-state”? That wasn’t how I originally intended the qualification–but this is a fair reading. So supposed you are such a Reductive Physicalist: How would you evaluate Joan’s statement? Would you say that Joan is incorrect? Not really. You would have to interpret what she said as if a counterfactual conditional (“if Singapore is located near the North Pole, it might snow a lot”). And given the additional qualification (“might not experience the other physical ailments that Philip suffers from”), he ought to accept Joan’s claim. Think of it the other way–if the Reductive Physicalist rejects Joan’s claim, he is basically saying that the “stress-understood-as a-purely-mental-state” always go together with those specific other physical ailments that Philip suffers from, and this is not something that he should accept at all.

Philip: “I have missed two weeks of class and the last time I checked we were still talking about God, so give me a minute to catch up… If there exists a sound argument proving the existence of the Classical Theistic God, and if such a God is an immaterial being, then it would show that Mind-Body Dualism is true as a theory of the mind, because it would prove that there exist things that are purely immaterial, right?”

Philip is wrong–at least as far as the concepts introduced in class are concerned (around Slide #13; also mentioned in the Q/A–do a CTRL-F for “God”). Mind-body Dualism and Physicalism were introduced as theories about the nature of the mind. In fact, we were focusing on the human mind, though the point can be generalized to cover other animals. A separate argument for the existence of an immaterial God doesn’t help the Mind-Body Dualist since it doesn’t show that we are composites of body and soul as two distinct substances. (11% of you picked this.)


  • Question 7

Option D (“Neither Gene nor Dave”). Most of you (88%) got this.

Gene is wrong. Not even Nagel himself thinks that his argument establishes the rationality of Mind-Body Dualism. The argument attempts to show that Reductive Physicalism–more specifically, Mind-Body Reductionism–is either false or at least unjustified given the present stock of concepts. Even assuming that the three theories are all the options (a big assumption), this still leaves a choice between Dualism and some Dual Aspect theory. (But actually, it’s worse than that–for all we know, none of the theories are rational; but we leave that aside.)

Dave is also wrong: Nagel’s argument is neutral regarding Mind-Body Dependence. After all, rejecting Mind-body Reductionism doesn’t entail rejecting Mind-Body Dependence..


  • Question 8 

Option C (“Lena, Abe and Tess only”). Most of you (80%) got this, with some (16%) distracted by Option B (“Joan, Lena and Abe only”). Looking at the distribution, almost all of you can see that Dave and Gene are wrong, and Lena and Abe are right. So it’s mainly Joan and Tess. Let’s consider each in turn, starting with the less divided ones.

Gene is wrong because he misunderstands what it means for a fact to be accessible only from a singular point of view. Nagel’s point isn’t that, e.g., chocolates can’t taste the same to all. He can grant that there’s an aspect that is entirely shared–how chocolate taste–while insisting that the experience of that taste is still from singular perspectives. And it is that latter feature of the experience that isn’t accessible from multiple points of views.

It also follows from the above that Dave is wrong and Lena is right. Recall that Nagel says that even if the scientist tastes chocolate by licking the brain of a chocolate-eater, he would have his taste of chocolate, not the chocolate-eater’s. (Most of you can see this.)

Abe is right because if the conceptual innovations involve logical impossibilities, then there is no such thing as explaining essential subjective facts in purely objective (physicalist) terms. No such explanation will succeed. All this is logically compatible with one believing logically impossible things.

As I said, almost all of you can see the above. Now for the remaining two.

Joan: “An assumption in Nagel’s argument is the normative claim that Reductive Physicalism (as a theory of mind) must tell us what consciousness really is. However, it is not necessary for a serious theory of mind like Reductive Physicalism to tell us what consciousness really is. After all, consciousness might not even be real–so why bother?”

Joan is wrong. Since consciousness significantly involves our experience of qualia which is an important type of mental phenomenon, a complete theory of the mind must account for our experience of qualia and therefore–consciousness (See Slide #27). It’s not like the Reductive Physicalist believes that conscious experience isn’t real in the sense that it doesn’t exist–they just think that whatever it is can be reduced to purely physical states.

Tess: “It is logically possible both that (i) Reductive Physicalism is false as a theory of mind, and (ii) if it is true, we don’t know how it can be so (given our present stock of concepts). This said, it is neither necessary nor sufficient for both (i) and (ii) to be true for Nagel’s argument to be sound.”

Tess is right. First of all, it’s possible for something both to be false and for us not to know how it could be true if it were true. Consider a contradictory claim, for instance–“this ball is both red all over and not red all over”. Not only is this statement false, it is also such that “if true, we don’t know how it can be so (given our present stock of concepts)”–notice also that the second disjunct doesn’t directly commit to the idea that the statement is true, only that if it is true, we don’t know how it is true.

Secondly, it’s not necessary for both (i) and (ii) to be true for Nagel’s argument to be sound. Nagel’s conclusion is true as long as either (i) or (ii) is true, even if it’s not true that both are. So both (i) and (ii) being true isn’t a necessary condition for the conclusion to be true, and so, not a necessary condition for the argument to be sound. Conversely, both (i) and (ii) being true isn’t a sufficient condition for Nagel’s argument to be sound. After all, they could be true for other reasons independent of Nagel’s argument.